God created mankind with an urgent compulsion to defend himself from all threats to his life, which is only sensible if His creation was to survive. That means mankind must have food, water, and shelter. One must add money (or some substitute) to the list since money is required to survive. (Sex is probably the second strongest urge of man, but that’s another article.)
Societies’ laws must reflect the fact of man’s basic urges. That is why it is not wrong to kill in defense of one’s own life or the life of others, especially family. When taking a wife, a man is obligated to be the protector as well as partner, parent, and provider. That’s one reason why every man should own a gun and know how to use it and be willing to use it if necessary.
This truth goes back to ancient Jewish law that gives a homeowner the right, even the duty, to kill a person during a night home invasion since he can expect the most dangerous intent. At night, a homeowner has limited knowledge of the threat to the family, while he can make a fair assessment of the threat in the daylight. However, if it is the daytime, a homeowner must try not to kill an intruder.